The basic objective of this study is to determine what effect dietary restriction has on the transfer of genetic information throughout the life span of an organism. In this study, male Fischer F 344 rats will be fed a laboratory chow diet ad libitum or sixty percent of ad libitum (restricted diet). The mean and maximum survival of these two groups of rats will be established. Periodically, the translational and transcriptional activities of several tissues from rats on the two dietary regimens will be determined. Using the post-mitochondrial supernatant from brain and kidney tissue and isolated hepatocytes, protein synthesis will be measured by the incorporation of radioactively-labeled L-valine into acid-insoluble material to determine the translational activities of these tissues from rats in this study. The transcriptioal activity of liver will be ascertained by measuring RNA synthesis by the ability of suspensions of hepatocytes to incorporate radioactively-labeled orotic acid-insoluble material. From this research, it will be possible to determine whether the increased longevity associated with dietary restriction is accompanied by a decrease in the synthesis of RNA or protein and/or a delay in the age-related changes in the synthesis of RNA or protein.